High levels of cortisol seen in stress and in animal models of aging have been associated with damage to the hippocampus, a brain region involved in learning and memory. Studies have shown an association between stress exposure and depression, as well as elevations in cortisol during depressive episodes. In addition, deficits in verbal memory were correlated with cortisol levels in depressed patients. Some studies, but not others, found decreased hippocampal volume measured with magnetic resonance imaging (MRI) in depressed patients.